Roundtable: Cellular/Wi-Fi Integration

This panel discussion on Cellular/Wi-Fi Integration is moderated by Alex Reznik, Sr. Principal Engineer at InterDigital, and includes Allan Jerrett, Director of Product Management in Network and Services Management at Alcatel-Lucent’s IP Division, and Todd Mersch, Director of Product-line Management in the Software and Solutions Group for RadiSys. Additional information on participants follows the discussion.

Alex:The topic for today’s roundtable is cellular/Wi-Fi integration, a subject important for all of our companies. We’ll take a short look at what each company is concentrating on in this area and then move on to the discussion.

At InterDigital, we’re focusing on fundamental policy-driven bandwidth management solutions that can factor in factor in a variety of information to effectively route wireless traffic across all available networks, and do so in a way that is subject to policy control via operator, user, or service provider policies. We’ve developed such network-side solutions as an integrated Femto-cell and Wi-Fi access point which we call the Converged Gateway (CGW), and a device client -- the Smart Access Manager, or SAM. The Smart Access Manager is something that we, for example, jointly successfully demonstrated with Alcatel-Lucent at this year’s Mobile World Congress.

Allan, can you briefly describe what Alcatel-Lucent is doing in this space?

Allan:We’re doing a number of things in Wi-Fi offload, including small cells with advanced Wi-Fi capabilities and our Wi-Fi gateway platform. My involvement relates to control aspects, in particular a Wi-Fi offload manager and policy control of Wi-Fi offload, via the ANDSF function. In other words, the server component of this solution that interacts with the InterDigital client to send policies, i.e. access point preference lists for Wi-Fi offload policies -- to the client. This is an emerging technology, so I expect that there will be plenty of experimentation with various use cases.

The Alcatel-Lucent approach is to use our policy platform, the Dynamic Services Controller platform, which is a flexible rules-based system based on what we call Agile Rules Technology. This system is context-aware and enables different types of use cases. With Wi-Fi offload, it’s taking in the contextual information from the ANDSF clients. There is now a standard interface for this purpose, the S14 interface. We combine information from the client with other contextual information such as network load information, subscriber preferences, application usage, device type, roaming status, and partnered or owned access.

So, the Service Provider’s network or specifically the ANDSF server can evaluate these different contexts and determine when to offload subscriber traffic. This has really been our focus and the collaboration with InterDigital: developing around the ANDSF standard but also extending it, commercializing it, and giving operators the ability to author their specific use cases or rules for how and when they will offload traffic to Wi-Fi… and in combination with the end-user preferences.

Alex:Thank you, Allan.Todd, could you describe what RadiSys is doing?

Todd:Absolutely. Similarly, we’re quite heavily involved in the small cells and heterogeneous network movement, if you will, as an enabling technology company. We provide – on the cellular side – small cell software solutions for HSPA+ small cells as well as LTE small cells. With Wi-Fi integration and from a Wi-Fi operator perspective, we have collaborated at the small cell end of the network with InterDigital through the converged gateway concept. By bringing together our small cell technology and the converged gateway capabilities from InterDigital, the integrated bandwidth management capabilities allow the operator – based on operator policy – to leverage both licensed spectrum and unlicensed spectrum wireless interfaces and provide full mobility, aggregation and segregation capability across both interfaces.

The approach is bringing intelligence down to the edge of the network and delivering more of the future vision of heterogeneous networks. As you move deeper into the networks, we’ve been delivering a security gateway that is a complete implementation on a blade or as a standalone system that our customers – including our manufacturing customers – can integrate into a platform with other functionalities that already exist. And what we’ve done is, as part of that security gateway, we have implemented the tunnel terminating gateway functionality in the 3G, Wi-Fi integration space. So, this existing solution that we have is already providing an anchor point for mobility as the center, for delivering operator-managed services, as well as for billing and management in general. That same solution is evolving to support the evolved packet gateway functionality, from an LTE perspective as well as tracking the standards to continue to provide a more seamless Wi-Fi offload and management experience within the network.

So, what we are doing with the converged gateway is tackling the problem all the way down to the access point or in the RAN side of things as well as trying to meet operator requirements back towards the edge of the network and embedding it in a way that doesn’t require operators to come in and deliver a whole new network element. The point is to have the Tunnel Terminating Gateway functionality or the Evolved Packet Data Gateway functionality really embedded within a security gateway, which is going to be required at the edge of the networks where you’re integrating Wi-Fi as well as small cells, over untrusted backhaul.

Alex:Thanks, Todd. I want to focus a little bit on the topic of Wi-Fi offload. It is something that both of you mentioned and I want to ask both of you about your views on the evolution of Wi-Fi beyond just an offload solution; meaning, beyond something that the operators perhaps see as a backup plan to move some of the traffic to and towards a world where Wi-Fi is an integral part of the way that operators plan to provide both capacity and coverage. Do you see that evolution happening, and, if so, what are your thoughts on how it’s actually going to happen? Perhaps we’ll start with Allan?

Allan:Concerning offloading for capacity, it’s a question of effective load balancing between the different methods access available and ensuring the quality of experience is not lowered when using Wi-Fi access. Also, it should be seamless to the end user. This is the focus of most operators planning their managed Wi-Fi service.

There are some operators, however, who see Wi-Fi as the primary access and actually have partnerships for 3G access. Essentially, theirs is a Wi-Fi core network. They see Wi-Fi not as a backup, but as the primary access and cellular network filling out coverage.

Others are looking to see what else they can do with Wi-Fi. What are the right use cases for leveraging Wi-Fi? Some of these may be different service plans or pricing plans for Wi-Fi connectivity. In other words, how can Wi-Fi be used to differentiate or address certain segments of market?

Most of these concepts are quite early in terms of development. We’re still in the initial stages. There is room for innovation and different approaches and it’s not necessarily the first, or the most obvious use case that will win. For example, some planners are considering use cases, where the subscriber is doing video and it’s a quality-managed video, they will actually put that on Wi-Fi.

Here’s another example. When VoIP is rolled out with carrier-grade service, the natural inclination is to keep it on the 4G network.However, is there benefit to offloading to Wi-Fi, specifically a home Wi-Fi network? There are communities of Wi-Fi services where you’re connecting to other broadband residential customers and their home Wi-Fi service. There are also different use cases around the enterprise. And, some use cases even around mobility, for example, a subscriber traveling on a train.

So, we’re seeing some different takes on how to use Wi-Fi, how to monetize or differentiate your service on Wi-Fi. There is definitely a good proliferation of different use cases and we’ll continue to see innovative use cases that leverage Wi-Fi. It goes well beyond a managed load-balancing question.

Rich raises an interesting point and certainly visible light is a promising emerging technology. However, from a mass deployment point of view, it appears to be quite a few years away, while WiFi presents an existing deployed technology base that operators should (and do) take advantage of today. So, naturally, the present focus is on WiFi. But, to me, the big point here is that cellular operators are moving away from exclusive reliance on licensed spectrum and towards using whatever access technology makes sense in a particular location. And once they figure out how to incorporate one non-cellular technology into their networks, adding others gets that much easier. So WiFi is really paving the way for whatever will come next – be it millimeter-wave, light-based or something completely different.

I understand Rich's concerns about potential radiation damage to biological tissue but it seems to me that a long term solution would be to dramatically reduce the required transmit power of the handheld device.